[PATCH 4.13 34/44] l2tp: hold tunnel in pppol2tp_connect()

From: Greg Kroah-Hartman
Date: Thu Nov 16 2017 - 12:53:47 EST


4.13-stable review patch. If anyone has any objections, please let me know.

------------------

From: Guillaume Nault <g.nault@xxxxxxxxxxxx>


[ Upstream commit f9e56baf03f9d36043a78f16e3e8b2cfd211e09e ]

Use l2tp_tunnel_get() in pppol2tp_connect() to ensure the tunnel isn't
going to disappear while processing the rest of the function.

Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Signed-off-by: Guillaume Nault <g.nault@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/l2tp/l2tp_ppp.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -584,6 +584,7 @@ static int pppol2tp_connect(struct socke
u32 tunnel_id, peer_tunnel_id;
u32 session_id, peer_session_id;
bool drop_refcnt = false;
+ bool drop_tunnel = false;
int ver = 2;
int fd;

@@ -652,7 +653,9 @@ static int pppol2tp_connect(struct socke
if (tunnel_id == 0)
goto end;

- tunnel = l2tp_tunnel_find(sock_net(sk), tunnel_id);
+ tunnel = l2tp_tunnel_get(sock_net(sk), tunnel_id);
+ if (tunnel)
+ drop_tunnel = true;

/* Special case: create tunnel context if session_id and
* peer_session_id is 0. Otherwise look up tunnel using supplied
@@ -781,6 +784,8 @@ out_no_ppp:
end:
if (drop_refcnt)
l2tp_session_dec_refcount(session);
+ if (drop_tunnel)
+ l2tp_tunnel_dec_refcount(tunnel);
release_sock(sk);

return error;